Novel partial power flow solver for multi — terminal HVDC control

Accurate control of the power flowing through multi-terminal HVDC networks is necessary to ensure that maximum power is being absorbed from the offshore windfarms. The current literature implements a Power Flow Solver to achieve this control. However, it requires knowledge of the entire network and measurements from each converter. In this paper, a novel power flow solver is presented which only requires measurements from the converters directly connected to the converter of interest. This partial Power Flow Solver (partial PFS) proves to be robust, having lower measurement requirements and consistently achieves tracking within 10% of the power setpoint for the cases considered. The partial PFS was employed on a 5-Terminal simplified state-space VSC-HVDC network model that integrates windfarm generation, an offshore passive load, and onshore grid connected Converters. Both fibre-optic and satellite communication ware considered for the control of the PFS. Preliminary tests of the partial PFS under severe system operation showed that it had an acceptable response for both communication options. An upgraded partial PFS was also presented which increases the controller's accuracy.